On a computer, click the tape or use the arrow keys to move one sixteenth at a time. Page Up and Page Down jump a quarter inch. In Find the mark, press Enter to lock in your answer.
The lines tell you the fraction
Most tapes split each inch into 16 parts, and the lines get shorter as the parts get smaller.
- The longest line with a number is the inch.
- The next longest, right in the middle, is the half inch.
- The two lines halfway to the half are the quarters, 1/4 and 3/4.
- Shorter again are the eighths: 1/8, 3/8, 5/8 and 7/8.
- The shortest lines are the sixteenths, all the odd ones from 1/16 to 15/16.
| Sixteenths | Reads as | Line | Decimal |
|---|---|---|---|
| 1 | 1/16″ | sixteenth | 0.0625″ |
| 2 | 1/8″ | eighth | 0.125″ |
| 3 | 3/16″ | sixteenth | 0.1875″ |
| 4 | 1/4″ | quarter inch | 0.25″ |
| 5 | 5/16″ | sixteenth | 0.3125″ |
| 6 | 3/8″ | eighth | 0.375″ |
| 7 | 7/16″ | sixteenth | 0.4375″ |
| 8 | 1/2″ | half inch | 0.5″ |
| 9 | 9/16″ | sixteenth | 0.5625″ |
| 10 | 5/8″ | eighth | 0.625″ |
| 11 | 11/16″ | sixteenth | 0.6875″ |
| 12 | 3/4″ | quarter inch | 0.75″ |
| 13 | 13/16″ | sixteenth | 0.8125″ |
| 14 | 7/8″ | eighth | 0.875″ |
| 15 | 15/16″ | sixteenth | 0.9375″ |
| 16 | 1″ | inch | 1″ |
You'll notice the fraction's always written as small as it goes. The eighth sixteenth is 1/2, not 8/16, and the sixth is 3/8. Only the odd sixteenths keep 16 on the bottom. The inch fraction chart has every 64th with its decimal and millimeters if you need finer marks.
Reading a mark in three steps
- Find the inch. Take the last numbered inch line to the left of your mark. That's the whole number.
- Count the sixteenths. Count the small spaces from that inch line to your mark. Or skip the counting by spotting the nearest half or quarter and counting from there.
- Reduce it. If the count is even, halve the top and bottom until the top is odd. 6/16 becomes 3/8, and 12/16 becomes 3/4.
Take a mark 11 small spaces past the 4. It's 4 11/16″. A quicker way to see it: it's three sixteenths past the 1/2, and 8/16 plus 3/16 is 11/16.
Try these
Answers
- A is 3 1/2″: a half inch mark, 8 sixteenths past 3.
- B is 4 1/4″: a quarter inch mark, 4 sixteenths past 4.
- C is 4 11/16″: a sixteenth mark, 11 sixteenths past 4.
- D is 3 3/8″: an eighth mark, 6 sixteenths past 3.
- E is 4 15/16″: a sixteenth mark, 15 sixteenths past 4.
Other marks on a tape
- Every 16 inches many tapes highlight the number, often in red. That's a common spacing for wall studs, and six of those spaces fill an 8 foot wall.
- Small black diamonds show up on some tapes every 19.2 inches. Five of those spaces also make 96 inches, and they're used to lay out engineered joists and trusses.
- The hook at the end is loose on purpose. It slides by its own thickness, so you're measuring right whether you hook it over an edge or push it against a wall.
- The metric edge, on tapes that have one, is in millimeters. Each small line is 1 mm and every tenth line is a centimeter.
The stud spacing, diamond and hook details are from this guide to carpenter's tape measures.
Questions
What is the smallest mark on a tape measure?
On most tapes it's 1/16″, and that's what the trainer uses. Some precision tapes and rulers go down to 1/32″, and the inch fraction chart lists those too.
How do I read a measurement in feet?
Many tapes don't start over at 12. They keep counting inches, so 30 means 30 inches, or 2′ 6″. Divide by 12 for feet. The feet and inches calculator does that for you.
How do I add two tape readings?
Add the whole inches and the fractions separately, with the fractions over the same bottom number, or type both into the feet and inches calculator.
Is there an app for measuring jobs?
Yes. My Construction Calculator for Android adds, subtracts and divides feet, inches and fractions, and rounds the answer to the tape mark you choose.
Construction Calculator
Feet, inches and fractions with exact math, rounded to the mark you choose.